The invention relates to a process for the preparation of functionalized polymers, and to the resulting functionalized polymers.
The production of hydroxyl and carbonyl compounds by reacting olefins with carbon monoxide and hydrogen is known. The products contain, as a rule, one more carbon atom than the reacting olefin. The reaction requires a hydrocarbon-soluble catalyst, usually one containing cobalt, iron, nickel or rhodium atoms, i.e., metals selected from Group 8 of the Periodic Table of the Elements, in complex bond with at least one ligand consisting of a carbon monoxide molecule and often a second ligand containing an organic compound of an atom, such as phosphorus or arsenic, selected from Group 5a of the Periodic Table.
British patent specification No. 1,378,185 concerns a process for preparing a hydroxylated block copolymer by reacting, with carbon monoxide and hydrogen, an unsaturated block copolymer having at least one polymer block of an aromatic mono-alpha-alkenyl hydrocarbon and at least one polymer block of a conjugated diene hydrocarbon wherein the polymer block of the conjugated diene has a 1,2 or 3,4 microstructure content of between 0% and 30% and a 1,4 microstructure content of between 100% and 70%, the reaction with carbon monoxide and hydrogen being continued until substantially all of the unsatureation of the conjugated diene block(s) is removed, 10-100% thereof being replaced by hydroxymethyl groups and 90-0% thereof being replaced by hydrogen atoms. This known process may be carried out as a one-step process, but then relatively high hydrogen pressures are required.
Conversion of conjugated diene monomers into a polydiene block occurs in several ways using the lithium based catalysts, preferably lithium alkyls, employed according to the prior art. Polymerization of butadiene leads to a mixture of several types of polymer microstructures, known as cis-1,4, trans-1,4 and 1,2 microstructures. In the cis-1,4 and trans-1,4 structures, carbon arrangement is all in a line and no small side chains are formed; thus, the double bonds produced are internal in the backbone chain. In the 1,2 microstructure, a two-carbon vinyl group is present as a short side chain directly attached to the two remaining carbon atoms of the original diene monomer unit. All three types of microstructure may be present in a polydiene block, but conditions are known in the art to maximize or minimize any of the three types if so desired.
A fourth type of microstructure known as 3,4 structure is also formed when substituted conjugated diolefins are polymerized. This is the case when isoprene is used. Statements herein about polymers having 1,2 structure also apply to polymers having 3,4 microstructure.